* Former Murdoch chief says approved officials' payments
* Brooks says justified if "overwhelming public interest"
* Ex-editor said she made mistakes, regrets Page 3 attack
LONDON, Feb 27 (Reuters) - Rebekah Brooks, Rupert Murdoch's former British newspaper boss, told a London court on Thursday she had sanctioned payments to public officials "half a dozen times" but denied approving the illegal sums for which she is on trial.
Brooks is accused of authorising almost 40,000 pounds ($66,000) in illegal payments from a reporter on Murdoch's Sun tabloid to a Ministry of Defence (MoD) official while she was editor of the paper.
She denies a charge of conspiracy to commit misconduct in a public office, and other offences of conspiracy to hack phones and perverting the course of justice.
Furore over phone-hacking by journalists at the News of the World tabloid, which she also edited, led to the closure of the paper in 2011, rocked Murdoch's media empire and had repercussions across the British political establishment.
However, the offence relating to authorising illegal payments carries a potentially much lengthier jail sentence.
Giving evidence for a fifth day at London's Old Bailey court, Brooks said "there had to be an overwhelming public interest" to justify payments to officials and only in "very narrow circumstances".
Asked by her defence lawyer if she had ever sanctioned such payments, which is illegal, Brooks replied: "Yes, probably since I was deputy editor of the Sun, 1998 to 2009, a handful of occasions, half a dozen."
"CHEAP AT THE PRICE"
Brooks was asked about a series of stories she approved that the prosecution says relate to illegal payments by a Sun journalist, who cannot be named for legal reasons, to an MoD official.
Brooks said she had not known who the reporter's source was, nor that she was a public official. "He probably should have brought it to my attention, absolutely," she said.
The jury were also shown emails from the reporter asking Brooks to authorise payments to his "number one military contact", to which she replied: "Of course".
"Nothing would have flagged up to me that there was an issue with it," she told the court, adding she would not have been "policing" the reporter for any wrongdoing.
In one email, the reporter described a 4,500 pound ($7,500) payment for three of his stories as being "cheap at the price".
"I probably thought, yeah that's quite cheap at the price," she said.
Brooks said there was legitimate public interest in many of the stories and, although she had been unaware who the source was at the time, she hypothetically would have sanctioned payments for a few of them.
These related to reports of bullying of army recruits and a "war hero" quitting over the treatment of his troops.
"This was exactly the kind of campaign we were doing," she said. She told the jury there had been no reaction or complaint from the MoD about the stories or their origin, although the paper's campaigns had caused some political disquiet.
CRUEL AND HARSH ATTACK
"We did get some complaints from one source, that was the (then) Prime Minister Gordon Brown, he didn't like it obviously, it wasn't good for him," said Brooks, who said Murdoch had given her the Sun job partly because of her zeal for campaigning.
Earlier Brooks, who edited Murdoch's News of the World and Sun tabloids from 2000 to 2009, told the court she had made lots of errors and regretted some stories and headlines.
"I personally made lots of mistakes", said the 45-year-old, who ran News Corp's British paper arm until 2011.
One case where she said she had "gone too far" was a personal attack on former Labour minister Clare Short over her opposition to daily pictures of topless models on page three of the Sun, a traditional feature of the paper since 1970.
The Sun, Britain's biggest-selling daily, had responded by publishing a doctored photograph of Short bare-breasted and accused her of being "jealous".
Brooks said this had been "cruel" and "harsh". "It was just too personal, it was just wrong," she added.
Her trial and that of six others continues.